<?php
/**
 * Created by PhpStorm.
 * User: daimingkang
 * Date: 2018/11/15
 * Time: 9:55 PM
 */

namespace App\Common\Tool;


class Mqtt
{
    private $socket;             /* holds the socket    */
    private $msgid = 1;            /* counter for message id */
    public $keepalive = 10;        /* default keepalive timmer */
    public $timesinceping;        /* host unix time, used to detect disconects */
    public $topics = array();     /* used to store currently subscribed topics */
    public $debug = false;        /* should output debug messages */
    public $address;            /* broker address */
    public $port;                /* broker port */
    public $clientid;            /* client id sent to brocker */
    public $will;                /* stores the will of the client */
    private $username;            /* stores username */
    private $password;            /* stores password */

    public $cafile;

    function __construct($address, $port, $clientid, $cafile = NULL)
    {
        $this->broker($address, $port, $clientid, $cafile);
    }

    /* sets the broker details */
    function broker($address, $port, $clientid, $cafile = NULL)
    {
        $this->address = $address;
        $this->port = $port;
        $this->clientid = $clientid;
        $this->cafile = $cafile;
    }

    function connect_auto($clean = true, $will = NULL, $username = NULL, $password = NULL)
    {
        while ($this->connect($clean, $will, $username, $password) == false) {
            sleep(10);
        }
        return true;
    }

    /* connects to the broker
        inputs: $clean: should the client send a clean session flag */
    function connect($clean = true, $will = NULL, $username = NULL, $password = NULL)
    {

        if ($will) $this->will = $will;
        if ($username) $this->username = $username;
        if ($password) $this->password = $password;


        if ($this->cafile) {
            $socketContext = stream_context_create(["ssl" => [
                "verify_peer_name" => true,
                "cafile" => $this->cafile
            ]]);
            $this->socket = stream_socket_client("tls://" . $this->address . ":" . $this->port, $errno, $errstr, 60, STREAM_CLIENT_CONNECT, $socketContext);
        } else {
            $this->socket = stream_socket_client("tcp://" . $this->address . ":" . $this->port, $errno, $errstr, 60, STREAM_CLIENT_CONNECT);
        }

        if (!$this->socket) {
            if ($this->debug) error_log("stream_socket_create() $errno, $errstr \n");
            return false;
        }

        stream_set_timeout($this->socket, 5);
        stream_set_blocking($this->socket, 0);

        $i = 0;
        $buffer = "";

        $buffer .= chr(0x00);
        $i++;
        $buffer .= chr(0x06);
        $i++;
        $buffer .= chr(0x4d);
        $i++;
        $buffer .= chr(0x51);
        $i++;
        $buffer .= chr(0x49);
        $i++;
        $buffer .= chr(0x73);
        $i++;
        $buffer .= chr(0x64);
        $i++;
        $buffer .= chr(0x70);
        $i++;
        $buffer .= chr(0x03);
        $i++;

        //No Will
        $var = 0;
        if ($clean) $var += 2;

        //Add will info to header
        if ($this->will != NULL) {
            $var += 4; // Set will flag
            $var += ($this->will['qos'] << 3); //Set will qos
            if ($this->will['retain']) $var += 32; //Set will retain
        }

        if ($this->username != NULL) $var += 128;    //Add username to header
        if ($this->password != NULL) $var += 64;    //Add password to header

        $buffer .= chr($var);
        $i++;

        //Keep alive
        $buffer .= chr($this->keepalive >> 8);
        $i++;
        $buffer .= chr($this->keepalive & 0xff);
        $i++;

        $buffer .= $this->strwritestring($this->clientid, $i);

        //Adding will to payload
        if ($this->will != NULL) {
            $buffer .= $this->strwritestring($this->will['topic'], $i);
            $buffer .= $this->strwritestring($this->will['content'], $i);
        }

        if ($this->username) $buffer .= $this->strwritestring($this->username, $i);
        if ($this->password) $buffer .= $this->strwritestring($this->password, $i);

        $head = "  ";
        $head{0} = chr(0x10);
        $head{1} = chr($i);

        fwrite($this->socket, $head, 2);
        fwrite($this->socket, $buffer);

        $string = $this->read(4);

        if (ord($string{0}) >> 4 == 2 && $string{3} == chr(0)) {
            if ($this->debug) echo "Connected to Broker\n";
        } else {
            error_log(sprintf("Connection failed! (Error: 0x%02x 0x%02x)\n",
                ord($string{0}), ord($string{3})));
            return false;
        }

        $this->timesinceping = time();

        return true;
    }

    /* read: reads in so many bytes */
    function read($int = 8192, $nb = false)
    {

        //    print_r(socket_get_status($this->socket));

        $string = "";
        $togo = $int;

        if ($nb) {
            return fread($this->socket, $togo);
        }

        while (!feof($this->socket) && $togo > 0) {
            $fread = fread($this->socket, $togo);
            $string .= $fread;
            $togo = $int - strlen($string);
        }


        return $string;
    }

    /* subscribe: subscribes to topics */
    function subscribe($topics, $qos = 0)
    {
        $i = 0;
        $buffer = "";
        $id = $this->msgid;
        $buffer .= chr($id >> 8);
        $i++;
        $buffer .= chr($id % 256);
        $i++;

        foreach ($topics as $key => $topic) {
            $buffer .= $this->strwritestring($key, $i);
            $buffer .= chr($topic["qos"]);
            $i++;
            $this->topics[$key] = $topic;
        }

        $cmd = 0x80;
        //$qos
        $cmd += ($qos << 1);


        $head = chr($cmd);
        $head .= chr($i);

        fwrite($this->socket, $head, 2);
        fwrite($this->socket, $buffer, $i);
        $string = $this->read(2);

        $bytes = ord(substr($string, 1, 1));
        $string = $this->read($bytes);
    }

    /* ping: sends a keep alive ping */
    function ping()
    {
        $head = " ";
        $head = chr(0xc0);
        $head .= chr(0x00);
        fwrite($this->socket, $head, 2);
        if ($this->debug) echo "ping sent\n";
    }

    /* disconnect: sends a proper disconect cmd */
    function disconnect()
    {
        $head = " ";
        $head{0} = chr(0xe0);
        $head{1} = chr(0x00);
        fwrite($this->socket, $head, 2);
    }

    /* close: sends a proper disconect, then closes the socket */
    function close()
    {
        $this->disconnect();
        stream_socket_shutdown($this->socket, STREAM_SHUT_WR);
    }

    /* publish: publishes $content on a $topic */
    function publish($topic, $content, $qos = 0, $retain = 0)
    {

        $i = 0;
        $buffer = "";

        $buffer .= $this->strwritestring($topic, $i);

        //$buffer .= $this->strwritestring($content,$i);

        if ($qos) {
            $id = $this->msgid++;
            $buffer .= chr($id >> 8);
            $i++;
            $buffer .= chr($id % 256);
            $i++;
        }

        $buffer .= $content;
        $i += strlen($content);


        $head = " ";
        $cmd = 0x30;
        if ($qos) $cmd += $qos << 1;
        if ($retain) $cmd += 1;

        $head{0} = chr($cmd);
        $head .= $this->setmsglength($i);

        fwrite($this->socket, $head, strlen($head));
        fwrite($this->socket, $buffer, $i);

    }

    /* message: processes a recieved topic */
    function message($msg)
    {
        $tlen = (ord($msg{0}) << 8) + ord($msg{1});
        $topic = substr($msg, 2, $tlen);
        $msg = substr($msg, ($tlen + 2));
        $found = 0;
        foreach ($this->topics as $key => $top) {
            if (preg_match("/^" . str_replace("#", ".*",
                    str_replace("+", "[^\/]*",
                        str_replace("/", "\/",
                            str_replace("$", '\$',
                                $key)))) . "$/", $topic)) {
                if (is_callable($top['function'])) {
                    call_user_func($top['function'], $topic, $msg);
                    $found = 1;
                }
            }
        }

        if ($this->debug && !$found) echo "msg recieved but no match in subscriptions\n";
    }

    /* proc: the processing loop for an "allways on" client
        set true when you are doing other stuff in the loop good for watching something else at the same time */
    function proc($loop = true)
    {

        if (1) {
            $sockets = array($this->socket);
            $w = $e = NULL;
            $cmd = 0;

            //$byte = fgetc($this->socket);
            if (feof($this->socket)) {
                if ($this->debug) echo "eof receive going to reconnect for good measure\n";
                fclose($this->socket);
                $this->connect_auto(false);
                if (count($this->topics))
                    $this->subscribe($this->topics);
            }

            $byte = $this->read(1, true);

            if (!strlen($byte)) {
                if ($loop) {
                    usleep(100000);
                }

            } else {

                $cmd = (int)(ord($byte) / 16);
                if ($this->debug) echo "Recevid: $cmd\n";

                $multiplier = 1;
                $value = 0;
                do {
                    $digit = ord($this->read(1));
                    $value += ($digit & 127) * $multiplier;
                    $multiplier *= 128;
                } while (($digit & 128) != 0);

                if ($this->debug) echo "Fetching: $value\n";

                if ($value)
                    $string = $this->read($value);

                if ($cmd) {
                    switch ($cmd) {
                        case 3:
                            $this->message($string);
                            break;
                    }

                    $this->timesinceping = time();
                }
            }

            if ($this->timesinceping < (time() - $this->keepalive)) {
                if ($this->debug) echo "not found something so ping\n";
                $this->ping();
            }


            if ($this->timesinceping < (time() - ($this->keepalive * 2))) {
                if ($this->debug) echo "not seen a package in a while, disconnecting\n";
                fclose($this->socket);
                $this->connect_auto(false);
                if (count($this->topics))
                    $this->subscribe($this->topics);
            }

        }
        return 1;
    }

    /* getmsglength: */
    function getmsglength(&$msg, &$i)
    {

        $multiplier = 1;
        $value = 0;
        do {
            $digit = ord($msg{$i});
            $value += ($digit & 127) * $multiplier;
            $multiplier *= 128;
            $i++;
        } while (($digit & 128) != 0);

        return $value;
    }


    /* setmsglength: */
    function setmsglength($len)
    {
        $string = "";
        do {
            $digit = $len % 128;
            $len = $len >> 7;
            // if there are more digits to encode, set the top bit of this digit
            if ($len > 0)
                $digit = ($digit | 0x80);
            $string .= chr($digit);
        } while ($len > 0);
        return $string;
    }

    /* strwritestring: writes a string to a buffer */
    function strwritestring($str, &$i)
    {
        $ret = " ";
        $len = strlen($str);
        $msb = $len >> 8;
        $lsb = $len % 256;
        $ret = chr($msb);
        $ret .= chr($lsb);
        $ret .= $str;
        $i += ($len + 2);
        return $ret;
    }

    function printstr($string)
    {
        $strlen = strlen($string);
        for ($j = 0; $j < $strlen; $j++) {
            $num = ord($string{$j});
            if ($num > 31)
                $chr = $string{$j}; else $chr = " ";
            printf("%4d: %08b : 0x%02x : %s \n", $j, $num, $num, $chr);
        }
    }

}